Insecticide Resistance and Its Intensity in Populations of Malaria Vectors in Colombia.

Insecticide resistance in malaria vectors threatens malaria prevention and control efforts. In Colombia the three primary vectors, Anopheles darlingi, An. nuneztovari s.l., and An. albimanus, have reported insecticide resistance to pyrethroids, organophosphates, carbamates, and DDT; however, the insecticide resistance monitoring is not continuous, and the data on the prevalence of resistance is scarce and geographically limited. We describe the resistance levels and intensity of previously detected resistant populations among primary malaria vectors from the most endemic malaria areas in Colombia. The study was carried out in 10 localities of five states in Colombia. Bioassays were carried out following the methodology of CDC Bottle Bioassay using the discriminating concentration and in order to quantify the intensity the specimens were exposed to 2, 5, and 10X discriminating concentrations. Five insecticides were tested: deltamethrin, lambda-cyhalothrin, alpha-cypermethrin, permethrin, and DDT. The results provide evidence of low resistance intensity and resistance highly localized to pyrethroids and DDT in key malaria vectors in Colombia. This may not pose a threat to malaria control yet but frequent monitoring is needed to follow the evolution of insecticide resistance.

Microgeographic genetic variation of the malaria vector Anopheles darlingi root (Diptera: Culicidae) from Cordoba and Antioquia, Colombia.

Anopheles darlingi is an important vector of Plasmodium spp. in several malaria-endemic regions of Colombia. This study was conducted to test genetic variation of An. darlingi at a microgeographic scale (approximately 100 km) from localities in Córdoba and Antioquia states, in western Colombia, to better understand the potential contribution of population genetics to local malaria control programs. Microsatellite loci: nuclear white and cytochrome oxidase subunit I (COI) gene sequences were analyzed. The northern white gene lineage was exclusively distributed in Córdoba and Antioquia and shared COI haplotypes were highly represented in mosquitoes from both states. COI analyses showed these An. darlingi are genetically closer to Central American populations than southern South American populations. Overall microsatellites and COI analysis showed low to moderate genetic differentiation among populations in northwestern Colombia. Given the existence of high gene flow between An. darlingi populations of Córdoba and Antioquia, integrated vector control strategies could be developed in this region of Colombia.

Laparoscopic-assisted endoluminal hybrid surgery: a stepping stone to NOTES.

BACKGROUND: Natural orifice transluminal endoscopic surgery (NOTES) is the anticipated progression of minimally invasive surgery. As it approaches, surgeons will need to develop the fundamental skills and spatial orientation needed to perform safely in this new field. The Natural Orifice Surgery Consortium for Assessment and Research has established several fundamental challenges to the safe introduction of NOTES. Our institutional experience with laparoscopic-assisted endoluminal surgery is reviewed to display the techniques and efficacy of procedures that address many of these challenges and may provide a safe transition for the general surgeon to NOTES or as an alternative to pure NOTES. METHODS: A retrospective review of all laparoscopic-assisted endoluminal surgeries from 1991 to 2007 was performed. Patients had been referred to the institution and selected after either unsuccessful attempts from traditional endoscopic resection of pathology by a gastroenterologist or being deemed an unfavorable candidate for traditional endoscopic resection. All procedures involved establishment of pneumoperitoneum, placement of trochar ports under laparoscopic visualization, balloon ports in gastric cases combined with endoscopy, intraluminal insufflation, coordinated resection of intraluminal pathology using both the endoscopic and laparoscopic instruments, and closure of the intraluminal port sites with intracorporeal suturing. RESULTS: A total of 175 procedures were performed from 1991 to 2007 using these techniques. These procedures varied and included laparoscopic monitored colonoscopic polypectomy, resection of gastric polyps, intraluminal cystgastrostomy, gastric ulcer resection, and foreign body removal. The average age was 55 years (range 38 to 75 y), length of operation 95 minutes (range 60 to 137 min), hospital stay 3.5 days, and 5 complications (2.8%). Of the total procedures, 18 (10.2%) patients were found to have malignancy on frozen section and preceded with a formal resection. There are no cancer recurrences to date with a mean follow up of 74 months (6 to 196 mo). CONCLUSIONS: Our institutional experience with these procedures seems to be a natural transition to developing skills for NOTES procedures and displays a safe and effective approach to a wide range of intraluminal pathology. The general surgeon in practice can use this union of laparoscopy and endoscopy using current instruments and technology for safe transition into the emerging field of NOTES, or even as an alternative to pure NOTES. Mastery of intraoperative endoscopy and intraluminal surgery will be essential to this transition.

Species composition and natural infectivity of anthropophilic Anopheles (Diptera: Culicidae) in the states of Córdoba and Antioquia, Northwestern Colombia

Malaria is a serious health problem in the states of Córdoba and Antioquia, Northwestern Colombia, where 64.4 percent of total Colombian cases were reported in 2007. Because little entomological information is available in this region, the aim of this work was to identify the Anopheles species composition and natural infectivity of mosquitoes distributed in seven localities with highest malaria transmission. A total of 1,768 Anopheles mosquitoes were collected using human landing catches from March 2007-July 2008. Ten species were identified; overall, Anopheles nuneztovari s.l. was the most widespread (62 percent) and showed the highest average human biting rates. There were six other species of the Nyssorhynchus subgenus: Anopheles albimanus (11.6 percent), Anopheles darlingi (9.8 percent), Anopheles braziliensis (6.6 percent), Anopheles triannulatus s.l. (3.5 percent), Anopheles albitarsis s.l. and Anopheles oswaldoi s.l. at < 1 percent; and three of the Anopheles subgenus: Anopheles punctimacula, Anopheles pseudopunctipennis s.l. and Anopheles neomaculipalpusat < 1 percent each. Two species from Córdoba, An. nuneztovari and An. darlingi, were found to be naturally infected by Plasmodium vivax VK247, as determined by ELISA and confirmed by nested PCR. All species were active indoors and outdoors. These results provide basic information for targeted vector control strategies in these localities.

Species composition and natural infectivity of anthropophilic Anopheles (Diptera: Culicidae) in the states of Córdoba and Antioquia, Northwestern Colombia.

Malaria is a serious health problem in the states of Córdoba and Antioquia, Northwestern Colombia, where 64.4% of total Colombian cases were reported in 2007. Because little entomological information is available in this region, the aim of this work was to identify the Anopheles species composition and natural infectivity of mosquitoes distributed in seven localities with highest malaria transmission. A total of 1,768 Anopheles mosquitoes were collected using human landing catches from March 2007-July 2008. Ten species were identified; overall, Anopheles nuneztovari s.l. was the most widespread (62%) and showed the highest average human biting rates. There were six other species of the Nyssorhynchus subgenus: Anopheles albimanus (11.6%), Anopheles darlingi (9.8%), Anopheles braziliensis (6.6%), Anopheles triannulatus s.l. (3.5%), Anopheles albitarsis s.l. and Anopheles oswaldoi s.l. at < 1%; and three of the Anopheles subgenus: Anopheles punctimacula, Anopheles pseudopunctipennis s.l. and Anopheles neomaculipalpusat < 1% each. Two species from Córdoba, An. nuneztovari and An. darlingi, were found to be naturally infected by Plasmodium vivax VK247, as determined by ELISA and confirmed by nested PCR. All species were active indoors and outdoors. These results provide basic information for targeted vector control strategies in these localities.

The use of porcine small intestinal submucosa as a prosthetic material for laparoscopic hernia repair in infected and potentially contaminated fields: long-term follow-up.

INTRODUCTION: The treatment of hernias remains controversial, with multiple prosthetic meshes being exalted for a variety of their characteristics. In the event of incarcerated/strangulated hernias and other potentially contaminated fields the placement of prosthetic material remains controversial because of increased risk of recurrence and infection. Porcine small intestinal submucosa mesh (Surgisis, Cook Bloomington, IN) has been demonstrated safe and feasible in laparoscopic hernia repairs in this scenario. We present our 5-year experience, with placement of Surgisis mesh in potentially or grossly contaminated fields. METHODS: From May 2000 to October 2006, 116 patients (52 male, 64 female) with 133 procedures were performed. Placement of Surgisis mesh for either incisional, umbilical, inguinal, femoral or parastomal hernia repairs in an infected or potentially contaminated setting were achieved, and studied in a prospective fashion. RESULTS: All procedures were laparoscopically with two techniques [intraperitoneal onlay mesh (IPOM) and two-layered "sandwich" repair]. Mean follow-up was 52 +/- 20.9 months. Thirty-nine cases were in an infected field and the rest in a potentially contaminated field. Ninety-one procedures were performed concurrently with a contaminated procedure. Twenty-five presented as intestinal obstruction, 16 strangulated hernias, and 17 required small bowel resection; 29 were inguinal hernias, 57 incisional, and 38 umbilical. In 13 patients more than two different hernias were repaired. Eighty-five percent 5-year follow-up was achieved, during which we identified 7 recurrences, 11 seromas (all resolved), and 10 patients reporting mild pain. Six second looks were performed and in all cases except one the mesh was found to be totally integrated into the tissue with strong scar tissue corroborated macro- and microscopically. CONCLUSIONS: In our experience the use of small intestine submucosa mesh in contaminated or potentially contaminated fields is a safe and feasible alternative to hernia repair with minimal recurrence rate and satisfactory results in long-term follow-up.

Laparoscopic intraluminal surgery for gastrointestinal malignancies.

INTRODUCTION: Intraluminal surgery began with the advent of endoscopy. Endoscopic endoluminal surgery has limitations; and its failure results in conventional open or laparoscopic interventions with increased morbidity. Laparoscopy-assisted intraluminal surgery is a novel alternative to open or laparoscopic surgery for a failed endoscopic endoluminal technique, minimizing the associated complications. Endoscopic resection of early gastric and duodenal cancers is restricted by the limited view of the endoscope, insufficient number of instrument channels, and inability to have adequate margins of resection without risking perforation. These cancers potentially can be treated by laparoscopy-assisted intraluminal surgery without resorting to major gastric or duodenal resection. This procedure is relatively easy to perform and oncologically effective. We present the experience of the Texas Endosurgery Institute (TEI) in treating early gastric and duodenal cancers, including large malignant polyps and carcinoid tumors, with laparoscopy-assisted endoluminal surgery. MATERIALS AND METHODS: The data for all patients with early gastric and duodenal cancers who underwent laparoscopy-assisted endoluminal surgery at TEI between 1996 and 2007 were prospectively recorded. All of the patients had been referred by the endoscopist as noncandidates for endoscopic resection. We prospectively collected data on preoperative diagnosis, operating time, estimated blood loss, postoperative complications, histopathology, and recurrence rate. All patients underwent endoluminal port placement under direct visualization after a pneumoperitoneum was established. Operations were performed in conjunction with upper endoscopy for assistance with port placement under endoluminal visualization, insufflation, and specimen retrieval. After the intraluminal portion of the operation was completed, the endoluminal port sites were closed with laparoscopic intracorporeal suturing. RESULTS: From 1996 to 2007, a total of 12 patients underwent laparoscopic endoluminal surgery. All cases were completed successfully, including 5 resections of early gastric cancer (stage I), 3 wedge resections of carcinoid tumor, 2 resections of duodenal adenocarcinoma, and 2 resections of a malignant polyp at the gastroesophagic junction; all the cases were completed with disease-free margins. No recurrence of the original pathology have been reported, and the complications were minimal. CONCLUSION: Laparoscopic intraluminal surgery for early gastric and duodenal cancer is a feasible alternative to open conventional therapies; and it is associated with a lower incidence of incisional hernia formation and a lower infection rate.

Long-term experience with the laparoscopic approach to perforated diverticulitis plus generalized peritonitis.

BACKGROUND: The treatment of perforated diverticulitis is changing form the current standard of laparotomy with resection, Hartmann procedure, and colostomy to a minimally invasive technique. In patients with complicated acute diverticulitis and peritonitis without gross fecal contamination, laparoscopic peritoneal lavage, inspection of the colon, and intraoperative drain placement of the peritoneal cavity appears to alleviate morbidity and improve the outcome. In this article, we report our experience of a laparoscopic peritoneal lavage technique with delayed definitive resection when necessary. METHOD AND MATERIALS: Records of patients who underwent intraoperative peritoneal lavage for purulent diverticulitis at the Texas Endosurgery Institute from April 1991 to September 2006 were retrospectively reviewed. RESULTS: Forty patients were included in the study, with a male/female ratio of 26:14. The average age was 60 years. Many had associated co-morbidities. The average operating time was 62 minutes. There were no conversions to an open procedure. Apart from mild postoperative paralytic ileus in six patients and chest infections in two, there were no significant peroperative or postoperative complications. Just over 50% underwent elective interval laparoscopic sigmoid colectomy. During the mean follow-up of 96 months, none of the other patients required further surgical intervention. CONCLUSION: Laparoscopic lavage of the peritoneal cavity and drainage is a safe alternative to the current standard of treatment for the management of perforated diverticulitis with or without gross fecal contamination. It is associated with a decrease in the overall cost of treatment; the use of a colostomy is avoided; patient improvement is immediate; and there is a reduction in mortality and morbidity as definitive laparoscopic resection can be performed in a nonemergent fashion. Perhaps the most important benefit, other than avoiding a colostomy, is the association of fewer wound complications such as dehiscence, wound infection, and the high risk of hernia formation. Laparoscopic lavage and drainage should be considered in all patients in whom medical and/or percutaneous treatment is not feasible. It carries minimal morbidity and should be considered the standard of care.

The use of bioabsorbable staple line reinforcement for circular stapler (BSG "Seamguard") in colorectal surgery: initial experience.

Of all the complications associated with colorectal surgery, the most devastating and constant, despite all techniques being performed properly is anastomotic leakage, especially in left colon and rectal resections with rates as high as 50% when the rectum is involved. In 2005, our center published the preliminary experience with the use of linear staple line reinforcement for colon surgery. The purpose of this paper is to present a series of cases using a new conformation of bioabsorbable reinforcement for circular staplers in 5 patients, 2 patients with rectal cancer, 2 patients with diverticular disease, and 1 patient with sigmoid cancer. These initial data are very promising and has encouraged us to continue using this device on further patients.

Laparoscopic right hemicolectomy for cancer: 11-year experience.

INTRODUCTION: Laparoscopic surgery has emerged as the gold standard for many intra-abdominal procedures. Laparoscopic colon surgery is now entering its second decade of practice, and although there are many papers focusing on surgery of the distal colon, only a few have been published regarding right sided lesion approached totally laparoscopically. OBJECTIVE: Present data collected-in a prospective manner from a single institute over an eleven year period, focusing on laparoscopic right hemicolectomy for malignancy. METHODS: Patients elected for laparoscopic right hemicolectomy for colon cancer were analyzed prospectively. From May 1991 to May 2002, 98 patients underwent attempted laparoscopic right hemicolectomy for cancer, 44 male and 54 female, with a mean age of 70.6 years, emergent and non emergent cases were included Patients who underwent a diagnostic laparoscopy and those converted immediately to open procedure were excluded from this study. RESULTS: Ninety-two patients were included in the study, eighty-two of these had a totally intracorporeal anastomosis created, and ten had an extracorporeal anastomosis performed. The mean operative time for the intracorporeal group was 136 minutes, and for the extracorporeal group was 159 minutes. The average number of lymph nodes harvested was 10.8 and the final pathologic analysis showed 26 tumors stage I, 24 stage II, 31 stage III and 17 stage IV. CONCLUSIONS: In experienced hands, laparoscopic colectomy can be performed safely and effectively for the treatment of both benign and malignant diseases of the right colon. This study reaffirms the contention that laparoscopic approach to colon cancer offers equivalent, or in some instances, greater oncologic safety when compared to the open technique.

Laparoscopic harvest of omental flaps for reconstruction of complex mediastinal wounds.

BACKGROUND: Omental harvest for complex poststernotomy mediastinal wounds has traditionally required a formal laparotomy in often high-risk patients, thus making it the procedure of last resort. METHODS: The charts of all patients who underwent a laparoscopic omental harvest at the Texas Endosurgery Institute were retrospectively reviewed. RESULTS: Seven patients, 4 males and 3 females with an average age of 65.1 +/- 6.3 years, with complex mediastinal wounds following coronary artery bypass grafting were studied. All patients underwent laparoscopic harvest of omental flaps based on the right gastroepiploic artery (3), the left gastroepiploic artery (1) or both (3), along with pectoralis major myocutaneous advancement flaps in 5 patients and partial-thickness skin graft and a vacuum-assisted closure device in 2 patients. The average operative time for the entire procedure was 196 +/- 54 minutes. Enteric feedings could be tolerated early postoperatively with a mean of 3.8 days. One death (14.2%) occurred. All surviving patients had excellent wound healing results at a mean follow-up of 19.1 months. CONCLUSION: Laparoscopic harvest of omental flaps for the reconstruction of complex mediastinal wounds is a valid and potentially less morbid alternative for the treatment of this infrequent but disastrous complication of open heart surgery.

Laparoscopic placement of hepatic artery catheter for regional chemotherapy infusion: technique, benefits, and complications.

Approximately 15% to 18% of patients diagnosed with colorectal cancers present with metastases confined to the liver. Although many may undergo a liver resection procedure, some will not be candidates for surgery or will have recurrence of liver disease within the first 2 years after liver metastasis resection. For this subset of patients, regional hepatic chemotherapy, including intra-arterial chemotherapy, has been shown to improve control of the disease and, in some cases, prolong survival. With the advent of laparoscopic surgery and its application to more and more advanced procedures, the possibility of laparoscopic placement of a chemotherapy infusion catheter in the hepatic artery with all the advantages of a minimally invasive approach appears to be a viable alternative in our hands. From November 1993 through February 2002, 20 patients (12 male, 8 female) successfully underwent laparoscopic placement of a hepatic artery infusion catheter at the Texas Endosurgery Institute. Correct placement of the catheter was confirmed by methylene blue injections via the hepatic artery catheter at the time of surgery. Chemotherapy was generally initiated in the immediate postoperative period. Mean age was 68.3 years (range, 46-82). Twelve of the patients (60%) had previously undergone abdominal surgery. There were 27 major laparoscopic procedures performed at the time of hepatic artery catheter placement. There were no conversions to an open procedure. Mean operative time was 186 minutes (range, 125-280), and mean blood loss was 132 mL (range, 20-300). These values include the 27 major concurrent laparoscopic procedures performed at the time of catheter placement, including 18 cholecystectomies, 7 colectomies, and 2 liver resections. Median hospital stay was 3 days (range, 3-25), with a median return to regular diet of 3 days. There were no intraoperative complications and no deaths secondary to catheter placement. There were 2 late complications, for an overall rate of 10%. For all 17 patients with residual hepatic disease whose chemotherapy was successfully instituted, regression of the metastases was evident by abdominal computed tomographic criteria and CEA levels. Laparoscopic hepatic artery catheterization is both feasible and safe. It incurs all the benefits of a minimally invasive procedure and can be performed at the time of laparoscopic colectomy to avoid the necessity of a second procedure.